/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate licenses this file
 * to you under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.  You may
 * obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.metadata;

import io.crate.metadata.sys.SysNodesTableInfo;
import io.crate.expression.reference.ReferenceResolver;
import io.crate.expression.reference.sys.node.NodeStatsContext;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

public class LocalSysColReferenceResolver implements ReferenceResolver<RowCollectExpression<NodeStatsContext, ?>> {

    private final Map<ColumnIdent, RowCollectExpression<NodeStatsContext, ?>> expressionMap = new HashMap<>();

    public LocalSysColReferenceResolver(Iterable<ColumnIdent> localAvailable) {
        for (ColumnIdent ident : localAvailable) {
            expressionMap.put(
                ident,
                SysNodesTableInfo.expressions().get(ident).create());
        }
    }

    @Override
    public RowCollectExpression<NodeStatsContext, ?> getImplementation(Reference ref) {
        return expressionMap.get(ref.column());
    }

    public Collection<RowCollectExpression<NodeStatsContext, ?>> expressions() {
        return expressionMap.values();
    }
}
